Charging device and charging method

ABSTRACT

Charging a secondary battery ( 39 ) provided within wireless headphones ( 15 ) is carried out in a reliable manner by a charger ( 16 ) when the wireless headphones ( 15 ) are not in use. An engaged section ( 30 ) and electrodes ( 31 ) are provided at the bottom portion of a case ( 20 ) of the headphones ( 15 ). An engaging section ( 37 ) constituted by a pawl and a contact member ( 38 ) is provided on a receptacle surface ( 36 ) of a supporting plate ( 35 ) on the side of the battery charger ( 16 ). In the event that the headphones ( 15 ) are then mounted on the battery charger ( 16 ) so that the engaged section ( 30 ) is engaged by the engaging section ( 37 ) on the side of the battery charger ( 16 ), the electrodes ( 31 ) of the headphones ( 15 ) are press-attached against the contact members ( 38 ) on the side of the battery charger ( 16 ) as a result of the leverage principle.

TECHNICAL FIELD

The present invention relates to a charging device and charging method,and particularly relates to a charging device and charging method wherean apparatus with a secondary battery built-in is mounted on a batterycharger so as to charge the secondary battery.

BACKGROUND ART

As shown in FIG. 9, in Japanese Patent Publication No. 2770389 (patentdocument 1), a charging device comprising wireless headphones 1 and atransmission device 2 is disclosed. An engaging recess 3 is formed at anupper end of a cabinet of a transmission device 2. The dimensions ofthis engaging recess 3 are substantially the same as the width of ahanger section 4 of the headphones 1 so as to receive a protrudingsection 5 at a substantially central portion of the hanger section 4.

When the headphones 1 are mounted on the transmission device 2 so thatthe protruding section 5 of the hanger section 4 inserts into theengaging recess 3, pins 6 erected at the engaging recess 3 are insertedto within holes 7 of the protruding section 5 so as to make contact withelectrodes within the holes 7. In this way, a secondary battery 8provided within the headphones 1 is charged by a power supply circuit onthe side of the transmission device 2.

Here, light-emitting elements 9 are provided at the transmission device2 and light-receiving elements 10 are provided at the headphones 1.Therefore, after the secondary battery 8 of the headphones 1 is chargedby this transmission device 2, while the headphones are detached foruse, it is possible for signals to be transmitted to the light-receivingelements 10 of the headphones 1 from the light-emitting elements 9 ofthe transmission device 2 using infrared rays etc. It is thereforepossible for audio to be played back using the headphones 1 withoutemploying a signal cable (refer to patent document 1).

Further, in Japanese Utility Model Laid-open Publication No. H7-22955(Japanese Patent Publication 2), there are disclosed wireless headphonesemploying a secondary battery as an operation power supply. It is thenpossible to open and close charging terminals for charging the secondarybattery using an opening and closing body interlocking with an operationsection of a switch for switching over the operating state of theheadphones. This makes it possible to prevent hair and skin from makingcontact with the charging terminals by opening and closing the chargingterminals using the opening and closing body when the headphones areworn on a person's head and therefore prevent corrosion of and defectivecontact with the charging terminals.

It is preferable for the operation of charging wireless headphones witha secondary battery built-in to be straightforward. Patent document 1and patent document 2 described above disclose charging devices wherethe secondary battery does not have to be removed from the headphoneswhere charging is possible as a result of mounting the headphones on thebattery charger. With these charging devices of the related art,charging is carried out by making contact between charging pins 6 andelectrodes as a result of utilizing the weight of the headphones 1. Itis therefore not possible to ensure a contact pressure that is greaterthan the dead weight of the headphones. This has the disadvantage thatthe connection of the pins 6 is not always stable. There is also aproblem that fine adjustment is necessary in order to correctly line upthe positions of the terminals on the headphone side and the pins on theside of the battery charger during the charging operation.

In order to resolve the aforementioned problems, it is advantageous forthe present invention to provide a charging device capable of ensuringsufficient connection pressure in excess of the weight of wirelessapparatus such as headphones etc. that does not require fine adjustmentin order for electrodes to make appropriate contact with a connectionmember.

DISCLOSURE OF THE INVENTION

A primary aspect of the invention of the application relates to acharging device where apparatus with a secondary battery built-in ismounted on a battery charger and charging of the secondary battery isperformed, characterized by an engaging section and a contact memberprovided on the battery charger side, and electrodes provided onapparatus side for supplying power to the secondary battery upon theengaged section engaging with the engaging section and the contactmember making contact. In the event that the apparatus is mounted on thebattery charger so as to be engaged as a result of engaging the engagedsection and the engaging section, the electrodes are press-attachedagainst the contact member with a force greater than the weight of theapparatus due to angular moment centered about the engaging section ofthe apparatus due to the weight of the apparatus. This may includeapparatus where a secondary battery is built-into the apparatus in sucha manner that changing of the battery is not possible or apparatus wherestorage is such that the built-in secondary battery can be changed.

In the event that the apparatus is mounted on the battery charger sothat the engaging section engages with the engaged section, it ispreferable for the electrodes to make contact with the contact membersat a position between a perpendicular line passing through the center ofgravity of the apparatus and the engaging section. Further, it is alsopreferable for the receptacle surface of the battery charger to formsubstantial circular arc shapes so that when the apparatus is made torotate at the receptacle surfaces so that the engaged section is engagedby the engaging section, the electrodes are stopped at a position wherecontact is made with the contact members.

Moreover, it is also preferable for the battery charger to be providedwith wireless transmission means and for the apparatus to be providedwith wireless receiving means so that the receiving means of theapparatus and the output means supplied with the output of the receivingmeans are driven by the secondary battery while the apparatus is removedfrom the battery charger when in use. It is also preferable for signalsto be transmitted between the transmission means and the receiving meansusing infrared rays. In this event, it is preferable to provide aninfrared generator at the battery charger and to provide an infraredreceiver at the apparatus. It is also preferable for the apparatus to bewireless headphones. Further, it is also desirable for the cases for theoutput units of the headphones to be substantially circular or oval inshape so that the outer peripheries of the cases rotate along thesubstantially circular arc-shaped receptacle surfaces of the batterycharger so as to be stably supported at a position where the engagedportions are engaged by the engaging portions.

A further important aspect of the invention of this application relatesto a charging device provided with apparatus employing wirelesscommunication, and a battery charger serving a dual purpose of amounting table for mounting the apparatus when the apparatus is not inuse. Receiving means for receiving signals in a wireless manner areprovided on the side of the apparatus. Transmitting means fortransmitting signals to the apparatus in a wireless manner are providedon the side of the battery charger. Electrodes and an engaged sectionare provided on the side of the apparatus, and contact members andengaging section are provided on the side of the battery charger. In theevent that the apparatus is mounted on the battery charger so that theengaged section engages with the engaging section, the electrodes arepushed against the contact members due to angular moment taking theposition of engagement of the engaged section and the engaging sectionas a fulcrum due to the weight of the apparatus.

It is also preferable for the electrodes to be provided at the lowerportion of the apparatus so that in the event that the apparatus ismounted on the battery charger, the electrodes are press-attachedagainst the facing contact members provided on the receptacle surfacesof the battery charger.

A further important aspect of the invention relates to a charging methodwhere apparatus with a secondary battery built-in is mounted on abattery charger and charging of the secondary battery is performed,characterized by an engaging section and contact members being providedon the side of the battery charger, and electrodes for supplying powerto the secondary battery upon engaged sections engaging with theengaging section and the contact members making contact. In the eventthat the apparatus is mounted on the battery charger so that the engagedsection is engaged by the engaging section, the electrodes arepress-attached against the contact members with a force greater than theweight of the apparatus due to angular moment centered about theengaging section of the apparatus due to the weight of the apparatus, sothat power is supplied via the contact members and the electrodes so asto charge the secondary battery.

In the event that the apparatus is mounted on the battery charger sothat the engaging section engages with the engaged section, it isdesirable for the electrodes to make contact with the contact members ata position between a perpendicular line passing through the center ofgravity of the apparatus and the engaging section.

A preferred embodiment of the invention incorporated in the applicationalso comprises a headphone system comprising a battery charger, withheadphones having a secondary battery or other chargeable power supplybuilt-in, and has support sections for fixing the headphones when theheadphones are mounted on the battery charger. Engaging mechanisms forpreventing the headphones from falling due to rotation of body housingsections are provided at corresponding portions on both sides.Electrical contact points are then positioned between the engagingmechanism and the position of the center of gravity of the headphoneswhile fixed to the battery charger when viewed from a horizontaldirection.

The headphone system of the above embodiment may be a wireless headphonesystem employing infrared transmission. It is also possible for thebattery charger and the transmitter of the wireless headphone system tobe combined. A wireless headphone system employing electromagnetictransmission in place of infrared transmission is also possible in theabove embodiment. It is also possible for the battery charger and thetransmitter of the wireless headphone system of the above embodiment tobe integrated. A headset system capable of two-way communicationemploying the above structure is also preferable. In the case of aheadphone system capable of two-way communication, it is appropriate forinformation such as charge remaining in the secondary battery to be sentfrom the headphones to the battery charger side.

The above configuration may be employed in recording or playback ofaudio, or in headphone systems having two-way functions.

The headphone device of the aforementioned embodiment ensures sufficientcontact pressure for electrical contacts during charging and is capableof reliable connections. Making the shapes of the supporting sections ofthe battery charger similar to the shape of the headphones is effectivein making fixing of the headphones straightforward.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view showing a charging device using abattery charger.

FIG. 2 is a side view showing an operation for installing a headphone.

FIG. 3 is a side view showing a state of contact between electrodes andcontact members in the event of installation.

FIG. 4 is a block view showing a system for transmitting and receivingsignals in a wireless manner.

FIG. 5 is a circuit diagram of a transmission circuit of batterycharger.

FIG. 6 is a circuit diagram of a receiving circuit on the headphoneside.

FIG. 7 is an exploded perspective view showing a further embodiment ofan operation for installing headphones.

FIG. 8 is a side view of the state when installation of headphones iscomplete.

FIG. 9 is an exploded perspective view showing a charging device for asecondary battery for headphones of the related art.

BEST MODE FOR CARRYING OUT THE INVENTION

The following is a description of preferred embodiments of the presentinvention incorporated in this application. FIG. 1 to FIG. 6 are viewsshowing a wireless headphone charging device of a first embodiment ofthis application. First, a description is given of structuralcharacteristics using FIG. 1 to FIG. 3.

The charging device is comprised of wireless headphones 15 and a batterycharger 16 for charging the headphones 15. The battery charger 16 alsoserves a dual purpose as the transmission means, with a plurality ofinfrared light-emitting elements 17 being arranged in a row at an upperportion of the front surface side at a central portion of this box. Theinfrared light emitting elements 17 are constructed from diodes emittinginfrared rays and are covered by a cover 18.

The headphones 15 are equipped with a pair of flat, plate-shaped cases20 constituting an output unit. The cases 20 are substantially circularor oval as viewed from the side, with pads 21 being fitted to portionson the sides making contact with the ears. The pair of cases 20 is alsolinked together by a hanger 22. Both ends of the hanger 22 then formarms 23 splitting into two, with the cases 20 being supported in amanner so as to swing freely supported at fulcrums 24 of the arms 23.

A pressing section 27 pressing the top of a person's head is arranged atthe lower side of the hanger 22. The pressing section 27 is connected toportions at both ends of the hanger 22 by a retractable connecting belt28 projecting from both ends. Respective pairs of light-receivingelements 29 are housed in the arms 23 of the hanger 22.

A recess 30 constituting an engaged section is formed at an outerperipheral surface at a lower end side of one of the left and right pairof cases 20 of the headphones 15, for example, at the left side case 20.A pair of electrodes 31 is then formed at positions offset in acircumferential direction with respect to the recess 30.

Supporting plates 35 bent respectively in the shape of circular arcs areprovided on both sides of a battery charger 16 on which the cases 20constituting output units of the headphone 15 are mounted, with theupper surfaces of the supporting plates 35 constituting receptaclesurfaces 36. The radius of curvature of the arc in which the receptaclesurfaces 36 curve is a value slightly larger than the radii of the cases20 so as to ensure that the surfaces of the cases 20 of the output unitscan rotate smoothly along on the receptacle surfaces 36. An engagingsection 37 constituted by a pawl is provided so as to project from areceptacle surface 36, with pairs of contact members 38 being providedat positions to the rear of the pawl of the engaging section 37.Charging of a secondary battery 39 on the side of the headphones 15 isthen carried out as a result of the contact members 38 making contactwith electrodes 31 of the cases 20 of the headphones 15.

A wireless headphone device is therefore configured from the batterycharger 16 and the headphones 15. Namely, as shown in FIG. 4, atransmitter 16 of the battery charger constituting the transmitter isconnected to audio apparatus and the light-emitting elements 17 of thetransmitter 16 generate infrared rays. When the infrared rays are thenreceived by the light-receiving elements 29 of the receiver constitutedby the headphones 15, the receiver 15 demodulates and amplifies thereceived signal so as to drive the playback units 62 and 66.

FIG. 5 shows the electrical configuration on the side of the batterycharger 16 generating signals using infrared rays. Here, an automaticgain control (AGC) circuit 41 is connected to a signal terminal on theleft side, the AGC circuit 41 is further connected to an FM modulator42, and an output terminal of the FM modulator 42 is connected to thebase of a transistor 43. An AGC circuit 44 is connected to a right-sidesignal terminal, and an output terminal of the AGC circuit 44 isconnected to an FM modulator 45. An output terminal of the FM modulator45 is connected to the base of a transistor 46.

An emitter of the transistor 43 is connected to the bases of transistors51 and 54, and the emitter of the transistor 46 is connected to thebases of transistors 52 and 53. Collectors of the transistors 51 and 52are connected in series to series circuits (cathode side) of pairs ofinfrared light-emitting elements 17. Further, collectors of thetransistors 53 and 54 are also connected in series to series circuits(cathode side) of pairs of infrared light-emitting elements 17.

Next, as shown in FIG. 6, the receiving circuit on the side of theheadphones 15 is equipped with an amplifier 57 connected to a parallelcircuit of the phototransistors 29 for signal receiving use, with theamplifier 57 in turn being connected to an LR splitter 58. An outputterminal of the left side channel of the LR splitter 58 is connected toan amplifier 59, and an output of the amplifier 59 is connected to an FMdemodulator 60. An output terminal of the FM demodulator 60 is connectedto the playback unit 62 via an output amplifier 61. A converterconfigures the playback unit 62 of the left side of the headphones 15.

An output terminal of the right side channel of the LR splitter 58 isconnected to the amplifier 63. An output terminal of the amplifier 63 isthen connected to an FM demodulator 64. The output side of the FMdemodulator 64 is connected to the playback unit 66 via an outputamplifier 65. A converter configures the playback unit 66 of the rightside of the headphones 15.

A description is now given of the charging operation of the chargingdevice of the configuration described above. As shown in FIG. 1 and FIG.2, the headphones 15 are mounted on the battery charger 16. The pair ofcases 20 connected by the hanger 22 as described above are provided atthe headphones 15, and the cases 20 are mounted on the receptaclesurfaces 36 of the supporting plates 35 on both sides of the batterycharger 16. At this time, as shown in FIG. 2, the headphones 15 aremounted on the battery charger 16 in such a manner that the portions atthe sides of the lower ends of the left and right casings 20 where theelectrodes 31 are provided are positioned to the rear sides of thecontact members 38 of a receptacle surface 36 of the battery charger 16.

As shown in FIG. 3, casings 20 of the headphones 15 are then made torotate in a counterclockwise direction along the circular arc-shapedsurfaces on the receptacle surfaces 36 bent in circular arcs of thesupporting plates 35 of the battery charger 16. In doing so, the engagedsection 30 at the lower end of the casing 20 of the headphones 15engages with the pawl 37 of a receptacle surface 36 of the batterycharger 16. At this event, the electrodes 31 on the side of the casing20 are stopped in a state of contact with the contact members 38 of thebattery charger 16 as shown in FIG. 3. Namely, the electrodes 31 of theheadphones 15 and the contact members 38 of the battery charger 16 areconnected to each other. Power is therefore supplied to the secondarybattery 39 of the headphones 15 from the power supply circuit providedwithin the battery charger 16 via the contact members 38 and theelectrodes 31 so that the secondary battery 39 is charged.

According to the leverage principle, the electrodes 31 on the side ofthe headphones 15 and the contact members 38 of the battery charger 16are press-attached together during the charging operation with a forceof a magnitude greater than the weight of the headphones 15. This theoryis described in the following.

Now, the center of gravity of the headphones 15 is taken to be G in FIG.3, and an engagement point of an engaged section 30 constituting thefulcrum of the rotation action of the headphones 15 and an engagingsection 37 is taken to be F. A point of intersection of a perpendicularline from G and a horizontal line passing through F is then taken to beA, and a reaction force exerted by the headphones 15 coming from thebattery charger 16 at a point at a central portion of the pair ofelectrodes 31 is taken to be P. A perpendicular extremity goingdownwards from F with respect to P is taken to be B. A distance betweenF and A is taken to be L1, and a distance between F and B is taken to beL2.

Angular moment due to weight W of the headphones 15 acting on the centerof gravity G attempting to cause rotation in an counterclockwisedirection taking F as center is taken to be W·L1. With regard to this,at point B, the headphones 15 are subjected to a rotational force in aclockwise direction due to the reaction force P incurred by theelectrodes 31. This force is P·L2. Namely, the headphones 15 aresubjected to a moment P·L2 attempting to rotate the headphones 15 in aclockwise direction taking F as center. However, the headphones arestopped at the angle shown in FIG. 3. This is therefore balanced by amoment in the opposite direction taking F as center. As a result, thenext equation holds true.W·L1=P·L2And, therefore, P=W·L1/L2. As becomes clear from FIG. 3, P becomes avalue larger than W because L1 is larger than L2. The contact pressurebetween the electrodes 31 and the contact members 38 is therefore avalue larger than the weight of the headphones 15. The electrodes 31 ofthe headphones 15 and the contact members 38 of the battery charger 16therefore make contact in a more reliable manner with a stronger forcedue to the so-called the leverage principle.

Next, a description is given of the in-use operation of the transmissiondevice constituted by the battery charger 16 and the headphones 15. Thebattery charger 16 shown in FIG. 4 serves a dual purpose as atransmitter so that a signal taking infrared rays (the arrow of thedotted line) as a medium is supplied to the headphones 15 in a wirelessmanner by the light-emitting elements 17. The headphones 15 then receivethis signal using the light-receiving elements 29, left and right audiosignals are played back by the receiving circuit provided at the centerof the headphones, and playback units 62 and 66 are driven. The personwearing the headphones 15 can therefore listen to audio in a wirelessmanner.

An audio signal is supplied to left and right input terminals of thereceiving circuit of the battery charger 16 as shown in FIG. 5. The leftand right audio signals are supplied to the FM modulators 42 and 45 viathe AGC circuits 41 and 44 where the left and right audio signals areFM-modulated. The FM-modulated outputs are then supplied to transistors43 and 46 constituting buffers. The transistor 43 controls the basecurrent of transistors 51 and 54 and the transistor 46 controls the basecurrent of the transistors 52 and 53. The transistors 51 to 54 areconnected to series circuits of infrared light-emitting elements 17. Aninfrared signal that is the left and right audio signals FM-modulated asa result of the conduction of the transistors 51 to 54 is thereforegenerated by the light-emitting elements 17. It is preferable forcarrier waves of the FM modulators 42 and 45 FM modulating the left andright audio signals to be different.

Light generated by the infrared light-emitting elements 17 of thebattery charger 16 passes through the cover 18 so as to be received bythe light-receiving elements 29 of the headphones 15. As shown in FIG.6, current detected by the light-receiving elements 29 is amplified bythe amplifier 57 and split into FM-modulated signals corresponding tothe left and right audio signals by the LR splitter 58. The dividedsignals are then amplified by the amplifiers 59 and 63, and demodulatedto audio signals by the FM demodulators 60 and 64. The demodulated audiosignals are then amplified by the amplifiers 61 and 65 and drive theplayback units 62 and 66 constituted by converters. Playback of theaudio signal is therefore carried out as a result.

Next, a description is given of further embodiments using FIG. 7 andFIG. 8. The charging device of this embodiment is also constructed fromheadphones 15 and a battery charger 16. Here, the headphones 15 are suchthat arms 23 at both ends of the hanger 22 are fitted directly to thecases 20 of the output units. It is therefore not possible to swing thecases with respect to the arm 23. In other words, the angle of theheadphones with respect to the ears is adjusted by the extent ofdeformation of the hanger 22. With this kind of structure, theheadphones 15 are one size smaller in comparison with the headphones(refer to FIG. 1 to FIG. 3) of the first embodiment.

On the other hand, the battery charger 16 is equipped withirregular-shaped box-type supporting plates 35 on both sides, withbottom surfaces of these supporting plates 35 constituting receptaclesurfaces 36. Moreover, the engaging section 37 constituted by a pawl andcontact members 38 are provided at a receptacle surface 36. The engagingsection 37 engages with the engaged section 30 on a side of theheadphones 15 and the contact members 38 make contact with electrodes 31on the side of the headphones 15.

The headphones 15 are therefore such that the cases 20 can easily behoused within the supporting plates 35 so that when the headphones inthis state are rotated in an counterclockwise direction as shown by thearrow in FIG. 8, the recesses 30 provided at the bottom portions of thecases 20 of the headphones 15 engage with the engaging section 37 on thereceptacle surfaces 36 of the supporting plates 35 of the batterycharger 16. At this time, at the same time, electrodes 31 on the side ofthe headphones 15 are press-attached onto the contact members 38 at thesides of the battery charger 16. This pressing-on operation is due toangular moment generated by gravitational force passing through thecenter of gravity of the headphones 15 taking the engaging section 37 ascenter. This means that the electrodes 31 are pushed onto the contactmembers 38 with a pressing force that is larger than the pressing forcedue to the weight of the headphones 15. It is therefore possible in theabove embodiment to attain the same operational effects as for the firstembodiment described above.

In the above, a description is given of the invention incorporated inthis application using preferred embodiments as shown in the drawingsbut the invention incorporated in this application is by no meanslimited to the above preferred embodiments, and various modificationsare possible while still remaining within the scope of the technologicalconcept of the invention incorporated in this application. For example,the headphones 15 and the battery charger 16 of the above embodimentstransmit and receive signals in a wireless manner using infrared rays.It is also possible to transmit and receive signals usingelectromagnetic radiation rather than infrared rays. Further, thebattery charger 16 charges a secondary battery 39 of the headphones butthis is by no means limited to headphones 15 and a broad range ofapplications to charging secondary batteries of various other types ofapparatus operating in a wireless manner.

INDUSTRIAL APPLICABILITY

A primary aspect of the invention of the application is a chargingdevice where apparatus with a secondary battery built-in is mounted on abattery charger and charging of the secondary battery is performed.Here, engaging sections and contact members are provided on the side ofthe battery charger, and electrodes for supplying power to the secondarybattery upon engaged sections engaging with the engaging sections andthe contact members making contact. In the event that the apparatus ismounted on the battery charger so that the engaged sections and theengaging sections engage, the electrodes are press-attached against thecontact members with a force greater than the weight of the apparatusdue to angular moment centered about the engaging sections of theapparatus due to the weight of the apparatus.

According to such charging device, angular moment due to the weight ofthe apparatus is therefore utilized in the contacting of the electrodesand the contact members. This means that the electrodes make contactwith the contact members in a reliable manner with a pressing forcegreater than the case where just the weight is used, so as to bringabout a more stable charging operation.

1. A charging apparatus for charging a secondary battery when mountingan apparatus having a built-in secondary battery on a battery charger,the charging apparatus comprising: the battery charger comprising anengaging section and a contact member; and an electrode for supplyingpower to the secondary battery upon establishing contact between anengaged section engaging with the engaging section and the contactmember, wherein when the apparatus is mounted on the battery charger soas to engage the engaged section with the engaging section, theelectrode is press-attached against the contact member with a forcegreater than a weight of the device due to an angular moment centeredabout the engaging section of the apparatus due to the weight of theapparatus, and a receptacle surface of the battery charger forms asubstantial circular arc shape wherein the engaged section is engaged bythe engaging section when the apparatus is turned on the receptaclesurface, and the electrode stops at a position where contact is madewith the contact member.
 2. The charging device according to claim 1,characterized in that, if the engaging section engages with the engagedsection when the apparatus is mounted on the battery charger, theelectrode makes contact with the contact member at a position between aperpendicular line passing through a center of gravity of the apparatusand the engaging section.
 3. The charging device according to claim 1,characterized in that the battery charger is provided with a wirelesstransmission means and the apparatus is provided with wireless receivingmeans, wherein the receiving means of the apparatus and an output meanssupplied with an output of the receiving means are driven by thesecondary battery when the apparatus is removed from the battery chargerfor use.
 4. The charging device according to claim 3, characterized inthat a signal is transmitted between the transmission means and thereceiving means by infrared ray.
 5. The charging device according toclaim 4, characterized in that an infrared generator is provided at thebattery charger and an infrared receiver is provided at the apparatus.6. The charging device according to claim 1, characterized in that theapparatus is wireless headphone.
 7. The charging device according toclaim 6, characterized in that an output unit case of the headphone hasa substantially circular or oval shape so that the outer peripheries ofthe case rotate along the substantially circular arc-shaped receptaclesurface of the battery charger so as to be stably supported at aposition where the engaged portions are engaged by the engagingportions.
 8. A charging device provided with an apparatus employingwireless communication, and a battery charger serving a dual purpose ofa mounting table for mounting the apparatus when the apparatus is not inuse, the charging device characterized by: the apparatus comprising areceiving means for receiving a signal in a wireless manner and thebattery charger comprising a transmitting means for transmitting signalsto the apparatus in a wireless manner; the apparatus comprising anelectrode and an engaged section, and the battery charger comprising acontact member and engaging section, wherein when the apparatus ismounted on the battery charger so that the engaged section engages withthe engaging section, the electrode is pushed against the contact memberwith a force greater than a weight of the apparatus due to an angularmoment taking a position of engagement of the engaged section and theengaging section as a fulcrum due to the weight of the apparatus.
 9. Thecharging device according to claim 8, characterized in that an electrodeis provided at a lower portion of the apparatus, wherein if theapparatus is mounted on the battery charger, the electrode ispress-attached against a contact member provided on a receptacle surfaceof the battery charger.
 10. A charging method for charging a secondarybattery when mounting an apparatus having a built-in secondary batteryon a battery charger, characterized by: providing an engaging sectionand a contact member on the battery charger side; and providing anelectrode for supplying power to the secondary battery by engaging theengaging section and the contact member by the engaged section at theapparatus side; wherein when the apparatus is mounted on the batterycharger so as to engage the engaged section with the engaging section,the electrode is press-attached against the contact member with a forcegreater than a weight of the device due to an angular moment centeredabout the engaging section of the apparatus due to the weight of theapparatus, and the secondary battery is charged by supplying power viathe contact member and the electrode.
 11. The charging method accordingto claim 10, characterized in that if the engaging section engages withthe engaged section when the apparatus is mounted on the batterycharger, the electrode makes contact with the contact member at aposition between a perpendicular line passing through a center ofgravity of the apparatus and the engaging section.